Investigation of excitation mechanism of iron atomic lines in a glow discharge plasma by Boltzmann distribution

The excitation mechanism of iron atomic lines with excitation energies from 4.1 to 7.0 eV were investigated by Boltzmann distribution in glow discharge plasma with variation of discharge parameters, such as the applied voltage, current and gas pressure. The plots lying at low excited energies well fitted a normal Boltzmann distribution, whereas the atomic at higher excitation energies show large deviation from the linear Boltzmann plots. A probable reason for these results is that the excitation to the lower excited levels is caused by a thermal collision; on the other hand, exciting of high-lying excited levels of iron atom raise from the collision between iron atoms and metastable atoms of argon or neon.